Such an immersion sampler is known from DE-OS 24 06 764. The immersion sampler described therein is used to determine the gas content of a molten metal. It has a sample chamber which lies in front of an additional chamber in which pressure regulation takes place by means of an inert gas stream. The inlet velocity of the molten metal into the sample chamber is thereby regulated. In addition, a gas inlet and a vacuum chamber are connected through valves to the ante-chamber of the immersion sampler, so that the pressure can be either increased or decreased, as desired, in the immersion sampler. By regulating the pressure in this way, the time of entry of the molten metal into the sample chamber is selected so that entry of slag into the testing chamber is prevented. In the area of inlet of the melt into the sample chamber there is a narrowing which effectuates a closing of the sample chamber after successful sampling, by means of the molten metal quickly solidifying at this location. Immersion samplers of this type are expensive, since they require means for the supply as well as evacuation of gases, in order to make pressure regulation possible. In order to enable the gas flow to bypass the sample chamber, such immersion samplers have a relatively complicated structure at their immersion end.
Another immersion sampler is known from DE-AS 12 66 024. According to this reference, the regulation of gas pressure in the sample chamber takes place by means of a piston-cylinder arrangement. By this pressure regulation the inlet velocity of the molten metal into the testing chamber is regulated, so that the development of pinholes or bubbles in the sample is avoided. This type of immersion sampler also has a high apparatus cost.
In view of the above prior art, it is the object of the present invention to produce an immersion sampler for molten metals, whose simple construction makes possible a sampling with low inlet velocity and with prevention of formation of pinholes and pores in the sample.